The goal of this project is to characterize the ERG of human subjects for a variety of stimulus conditions using the nonlinear systems caracterization procedure commonly called white-noise analysis. The first- and second-order Wiener kernels computed for a white-noise stimulus reflect adaptation effects and other retinal mechanisms (Koblasz, 1977). During the first year of the project we will concentrate on improving the average signal-to-noise of the ERG measurement, and will conduct a series of experiments aimed at resolving interactions between retinal color systems. During the second year of the project, we will consider spatial interactions. We will first attempt to characterize the ERG for small focal stimuli using counterphase techniques. We will then provide two spatially separated stimuli and hopefully resolve interactions between the two stimulated regions of the retina. If these experiments are successful, we will shrink the focal stimuli to smaller dimensions presenting an array of independent stimuli. This will map the characteristics of the retina analogous to static and dynamic perimetry testing.